Luminous windows or transparent emissive windows are windows that are transparent and look like ordinary windows when turned off and are luminous, i.e. emit light, when turned on. These windows may for instance be used for general lighting or for displaying a sign or logo.
Generally, a luminous window comprises a transparent polymer material acting as a light guide, which may be lit by means of a light source. The light guide may comprise scattering elements for extracting the light out of the light guide and, for instance, directing it into a room.
When the light is turned on, the light emitted from the luminous window has the same color as the light emitted from the light source. If the sign or logo is to have a plurality of colors, a plurality of luminous windows are needed, each window being associated with a respective light source emitting a respective color. The plurality of luminous windows are then arranged next to each other, forming the sign or logo. This arrangement could be improved in terms of, e.g., flexibility. There is thus a need for more flexible arrangements.